Description: This function creates a middle surface in a solid part and places this surface in a new part.
Usage:
1. DSI prompts:
> SELECT SURFACE
• . After surfaces are selected, DSI generates middle surfaces automatically
2. DSI prompts:
• TOGGLE ON/OFF MID SURFACES: display on/off generated middle surfaces.
• TOGGLE ON/OFF OTHER SURFACES: display on/off surfaces except middle surfaces.
• MID SURF OF TWO SURFACES: select two surfaces to generate middle surface.
• SURFACES OFFSET: select surfaces to offset, offset distance is half of the part thick.
• DONE: finish and exit this function.